Ambient RF Energy Harvesting

Abstract

In this paper, we present a study of ambient RF energy harvesting

techniques. The measurement of the ambient RF power density is

presented. The average of the density in broadband (1GHz-

3.5GHz) is in the order of -12dBm/m² (63µW/m²). Two systems

have been studied to recover the RF energy. The first is a

broadband system without matching circuit. The second is a

narrow band system (1.8-1.9GHz) with a matching circuit. The

rectifier circuit RF / DC and the choice of the load to optimize

the DC power recovered are presented.

The preliminary results indicate that the recovered energy is not

sufficient to directly power devices but could be stored in a

super-capacity or micro-batteries.